The present invention relates to wheelchairs and, in particular, to a novel tubular, hinged frame assembly including a slide-follower fold coordinating assembly, swing-away footrests and a folding back.
Historically, wheelchair designs have remained relatively static in their implementation, even though a variety of accessories have been developed to accommodate various needs of the chair user. The basic chair, however, is typically constructed about tubular side frames which are arranged relative to a scissors-acting folding mechanism to collapse the chair for storage or transport. These folding mechanisms, in turn, most typically are positioned at the approximate center of the chair, beneath the seat, with the hinge action occurring along a vertical transverse plane through the chair. While such a folding action accommodates an attendant pushing the chair from the rear handles, it is inconvenient for the unattended user. That is, the awkward positioning of the folding mechanism makes it difficult for the user to either partially collapse the chair to pass through narrow doorways and/or to completely collapse the chair, such as during entry and egress from an automobile.
As an alternative, therefore, to a vertical-acting folding mechanism, it is desirable that the mechanism be operable in a horizontal plane, and preferably along the longitudinal chair axis. Furthermore, it is preferable that the mechanism be positioned to be accessible by the seated user.
To the extent Applicant is aware of any folding mechanisms of the latter type, descriptions thereof can be found upon references to U.S. Pat. Nos. 4,577,878; 4,101,143; 4,323,133; 4,026,568; and 4,595,212. Of the various designs disclosed therein, probably the most relevant to the present invention are those disclosed in U.S. Pat. Nos. 4,026,568; 4,323,133 and 4,595,212. Each of these discloses a wheelchair frame including a pair of fore and aft hinge assemblies. Each hinge, in turn, comprises a pair of wings, each wing being pivotally secured to the chair side frames, as well as at a point intermediate thereto. Hinge action coordinating assemblies coupled between the frame hinges are also disclosed in the U.S. Pat. No. 4,323,133 and U.S. Pat. No. 4,595,212 patents, with the assembly of the latter patent also including a slide-follower latching mechanism.
While the subject invention bears some similarities to these latter designs, it is believed distinguishable in its combination, along with its novel arrangement of its hinge wings to the chair side frames and center. Hinge action is further controlled via a pair of scissors-acting control arms and concentrically mounted tubular members positioned in slide-follower relation which, along with an associated latch mechanism, provides enhanced accessibility to the seated user. Appurtenant folding back and swing-away footrest assemblies further enhance the ergonomics of the design.